Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/185—Acids; Anhydrides, halides or salts thereof, e.g. sulfur acids, imidic, hydrazonic or hydroximic acids
  • A61K31/205—Amine addition salts of organic acids; Inner quaternary ammonium salts, e.g. betaine, carnitine
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P11/00—Drugs for disorders of the respiratory system
  • A61P11/08—Bronchodilators
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P9/00—Drugs for disorders of the cardiovascular system
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P9/00—Drugs for disorders of the cardiovascular system
  • A61P9/08—Vasodilators for multiple indications
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C231/00—Preparation of carboxylic acid amides
  • C07C231/22—Separation; Purification; Stabilisation; Use of additives
  • C07C231/24—Separation; Purification
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C233/00—Carboxylic acid amides
  • C07C233/01—Carboxylic acid amides having carbon atoms of carboxamide groups bound to hydrogen atoms or to acyclic carbon atoms
  • C07C233/16—Carboxylic acid amides having carbon atoms of carboxamide groups bound to hydrogen atoms or to acyclic carbon atoms having the nitrogen atom of at least one of the carboxamide groups bound to a carbon atom of a hydrocarbon radical substituted by singly-bound oxygen atoms
  • C07C233/24—Carboxylic acid amides having carbon atoms of carboxamide groups bound to hydrogen atoms or to acyclic carbon atoms having the nitrogen atom of at least one of the carboxamide groups bound to a carbon atom of a hydrocarbon radical substituted by singly-bound oxygen atoms with the substituted hydrocarbon radical bound to the nitrogen atom of the carboxamide group by a carbon atom of a six-membered aromatic ring
  • C07C233/25—Carboxylic acid amides having carbon atoms of carboxamide groups bound to hydrogen atoms or to acyclic carbon atoms having the nitrogen atom of at least one of the carboxamide groups bound to a carbon atom of a hydrocarbon radical substituted by singly-bound oxygen atoms with the substituted hydrocarbon radical bound to the nitrogen atom of the carboxamide group by a carbon atom of a six-membered aromatic ring having the carbon atom of the carboxamide group bound to a hydrogen atom or to a carbon atom of an acyclic saturated carbon skeleton
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07B—GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR
  • C07B2200/00—Indexing scheme relating to specific properties of organic compounds
  • C07B2200/13—Crystalline forms, e.g. polymorphs

Definitions

• the present invention relates to a method of preparation of a highly pure salt of optically pure formoterol and to a polymorph thereof.
• Formoterol whose chemical name is (+/-) N-[2-hydroxy-5-[l-hydroxy- 2[[2-(p-methoxyphenyl)-2-propyl]amino]ethyl]phenyl]-formamide, is a highly potent and ⁇ 2 -selective adrenoceptor agonist having a long lasting bronchodilating effect when inhaled.
• the structure of formoterol is as shown:
• Formoterol has two chiral centers in the molecule, each of which can exist in two possible configurations. This gives rise to four combinations: (R,R), (S,S), (R,S) and (S,E).
• (R,R) and (S,S) are mirror images of each other and are therefore enantiomers; (R,S) and (S,R) are similarly an enantiomeric pair.
• the mirror images of (R,R) and (S,S) are not, however, superimposable on (R,S) and (8,R), which are diastereomers.
• Formoterol is presently available commercially only as a racemic diastereomer, (R,R) plus (S,S) in a 1:1 ratio, and the generic name formoterol refers to this enantiomeric mixture.
• the racemic mixture that is commercially available for administration is a dihydrate of the fumarate salt.
• Administration of the pure (R,R)-isomer also offers an improved therapeutic ratio.
• polymorphic behavior of drugs can be of crucial importance in pharmacy and pharmacology.
• Polymorphs are, by definition, crystals of the same molecule having different physical properties as a result of the order of the molecules in the crystal lattice.
• the differences in physical properties exhibited by polymorphs affect pharmaceutical parameters such as storage stability, compressibility and density (important in formulation and product manufacturing), and dissolution rates (an important factor in determining bio-availability).
• Differences in stability can result from changes in chemical reactivity (e.g. differential oxidation, such that a dosage form discolors more rapidly when comprised of one polymorph than when comprised of another polymorph) or mechanical changes (e.g.
• some polymorphic transitions may result in lack of potency or, at the other extreme, toxicity.
• the physical properties of the crystal may be important in processing: for example, one polymorph might be more likely to form solvates or might be difficult to filter and wash free of impurities (i.e particle shape and size distribution might be different between one polymorph relative to the other).
• Each pharmaceutical compound has an optimal therapeutic blood concentration and a lethal concentration.
• the bio-availability of the compound determines the dosage strength in the drug formulation necessary to obtain the ideal blood level. If the drug can crystallize as two or more polymorphs differing in bio-availability, the optimal dose will depend on the polymorph present in the formulation. Some drugs show a narrow margin between therapeutic and lethal concentrations.
• Chloramphenicol-3-palmitate (CAPP) is a broad spectrum antibiotic known to crystallize in at least three polymorphic forms and one amorphous form. The most stable form, A, is marketed.
• the invention relates to (R,R)-formoterol L-tartrate in the form of a crystalline solid comprising at least 95% of a polymorph having peaks at the diffraction degrees with the intensity shown below in an X-ray powder diffraction pattern:
• polymorph C this 36-peak polymorph, which has not been previously described in the literature, will be referred to as "polymorph C”.
• the invention in another aspect, relates to a process for producing this new polymorph.
• the process comprises stirring a slurry of polymorph (B) in water, isopropyl alcohol and at least 13% by weight toluene at 40-55° C.
• the (R,R)-formoterol L-tartrate resulting from the inventive process is in the form of a crystalline solid comprising at least 95%) of the most thermodynamically stable polymorph of (R,R)-formoterol L-tartrate.
• This polymorph which will henceforth be referred to as polymorph A, has 23 peaks at the diffraction degrees with the intensity shown in the following X-ray powder diffraction pattern:
• the invention in another aspect relates to a method for preventing bronchoconstriction or inducing bronchodilation in a mammal by administering the pure polymorph A.
• Pure, in the sense used herein, means containing less than 5% of other polymorphs of (R,R)-formoterol L-tartrate, less than 0.5%) of other chemical impurities and less than 2% of other optical isomers of formoterol.
• compositions comprising a pharmaceutically acceptable carrier and pure polymorph A of R,R- formoterol L-(+)-tartrate.
• FIG. 1 is an IR spectrum of R,R-formoterol L-(+)-tartrate, polymorph B.
• FIG. 2 is a differential scanning calorimetric (DSC) trace of R,R- formoterol L-(+)-tartrate, polymorph B.
• FIG. 3 is an x-ray powder diffraction pattern (XRDP) trace of R,R- formoterol L-(+)-tartrate, polymorph B.
• XRDP x-ray powder diffraction pattern
• FIG. 4 is an IR spectrum of R,R-formoterol L-(+)-tartrate, polymorph C.
• FIG. 5 is a differential scanning calorimetric (DSC) trace of R,R- formoterol L-(+)-tartrate, polymorph C.
• FIG. 6 is an x-ray powder diffraction pattern (XRDP) trace of R,R- formoterol L-(+)-tartrate, polymorph C.
• XRDP x-ray powder diffraction pattern
• FIG. 7 is an IR spectrum of R,R-formoterol L-(+)-tartrate, polymorph A.
• FIG. 8 is a differential scanning calorimetric (DSC) trace of R,R- formoterol L-(+)-tartrate, polymorph A.
• FIG. 9 is an x-ray powder diffraction pattern (XRDP) trace of R,R- formoterol L-(+)-tartrate, polymorph A.
• racemic 4-benzyloxy-3-nitrostyrene oxide was coupled with an optically pure (R,R)- or (S,S)-N-(l-phenylethyl)-N-(l-(p-methoxyphenyl)-2-propyl)amine to give a diastereomeric mixture of formoterol precursors, which were then separated by semipreparative HPLC and transformed to the pure formoterol isomers. Both syntheses suffer long synthetic procedure and low overall yield and are impractical for large scale production of optically pure (R,R)- or (S,S)-formoterol.
• the Trofast reference describes reacting 4.5 grams of the styrene oxide with 4.8 grams of the phenethylamine to produce 94 milligrams of the pure S,S enantiomer.
• the only practical, economical and efficient method for synthesizing optically pure formoterol is described in US patent 6,268,533 and PCT application WO 00/21487. The synthesis is outlined in Scheme I:
• Polymorph B exhibits 30 peaks at the diffraction degrees with the intensity shown below in an X-ray powder diffraction pattern:
• polymorph B As the (R,R)-formoterol L-tartrate separates in the initial crystallization from this process, it is predominantly in the kinetically favored form, polymorph B.
• Polymorph B is referred to in the '533 patent as P2. In pure form it exhibits a peak at about 179° C on differential scanning calorimetry and is soluble in water at 25° C to the extent of 26.7 mg/mL.
• US patent 6,268,533 describes the conversion of B to the thermodynamically most stable polymorphic form A.
• Polymorph A is referred to in the '533 patent as PI.
• Polymorph A exhibits a peak at about 193° C on differential scanning calorimetry and is soluble in water at 25° C to the extent of 15.4 mg/mL.
• the product described in '533 contains four identified chemical impurities (described below), and, no matter how many times the product is recrystallized, the resulting polymorph A contains at least 0.5% impurities. While not wishing to be held to any particular theory, applicants surmise that the conditions of recrystallization may result in the partial hydrolysis of the formamide to the amine:
• aniline 7 was formed by hydrolysis of the formamide group of 1, while 8 was generated as a result of dehydroxylation, and compounds 9 and 10 were formed by hydrogenation of the starting bromohydrin 3 and amine 4, respectively, excess reactants from the previous synthetic steps.
• impurities 9 and 10 were removed, the level of 8 decreased from 0.6% to 0.3%, and the level of 7 increased from 0.1 % to 0.2%.
• the polymorphs were identified at three stages of the process: (1) the crude crystalline solid generated after addition of L-tartaric acid to a solution of the crude free-base (crystal form B), (2) the crystalline solid formed after warming the slurry of the crude solid to effect the impurity removal (crystal form C) , and (3) the crystalline solid isolated after crystallization of the crude wet-cake from 25%> aqueous isopropyl alcohol (crystal form A).
• Polymorphs A and B had been observed before, and were reported in the US patent cited above.
• Polymorph C had never before been observed.
• the three polymorphs could be generated and interconverted according to Scheme II, demonstrating the concurrency of the impurity removal and polymorph interconversion.
• the isolated crude solid in crystal form B was suspended in a 1.8:1 w/w mixture of isopropyl alcohokwater at a concentration of 17 wt%>, warmed to 45-50 °C, and the conversion to form C and the impurity levels were monitored as a function of the amount of toluene in the solvent mixture (Table 3).
• Table 3 When the slurry was warmed to 45-50 °C for an extended period, no polymorph conversion was observed, nor was an impurity removal effected, when the amount of toluene in solution was 9 wt% or lower (entries 1-3). However, when the level of toluene was raised to 13 wt%, the impurity removal was observed (entry 4).
• Crystallization of polymorph B or polymorph C from aqueous isopropyl alcohol generated the same morphologically distinct solid, polymorph A. Dissolution of either crude solid in aqueous isopropyl alcohol at elevated temperatures, followed by cooling to 0-5 °C gave the crystallized solid.
• the IR spectrum, DSC trace, and X-ray powder diffraction pattern are shown in Figure 3.
• the IR spectrum is characterized by the broad singlet at 3420 cm " containing two shoulders, the singlet at 3115 cm “1 , and the broad nature of the absorbances in the 2300 - 3500 cm “1 range.
• the DSC shows a strong, sharp endotherm transition at 192 °C, and the X-ray powder diffraction spectrum contains a unique pattern.
• B may be converted to A either directly (by a process already described in US 6,268,533) or B may be converted to A via C by the newly discovered process.
• Both processes produce the same single polymorph of (R,R)-formoterol L-tartrate, uncontaminated with other polymorphic forms, but only the new process produces the single, thermodynamically most stable polymorph of (R,R)-formoterol L- tartrate in greater than 99.5% chemical purity.
• the optimized process uses a controlled manipulation of the polymorphs of (R,R)-formoterol L-tartrate as the method for providing the API with ⁇ 0.2%> of any single impurity and in the most thermodynamically stable crystal form A.
• Crystal forms B and C dissolve in aqueous isopropyl alcohol at a lower temperature than form A, form C can be generated in higher purity than form B, and form A is the most stable crystal form of the three polymorphs.
• Scheme III an optimized crystallization process has been developed (Scheme III): (1) formation of a slurry of crude polymorph B by addition of L- tartaric acid to a solution of the free-base, (2) in-situ conversion of form B to the highly pure form C, (3) isolation of crude polymorph C, (4) dissolution of form C in 50% aqueous isopropyl alcohol (50-55 °C), (5) immediate seeding of the solution with form A crystals (insoluble at 55 °C in 50%) aqueous isopropyl alcohol), (6) addition of isopropyl alcohol to decrease the water content to 25% and effect a rapid cooling of the mixture to 40-45 °C, and (7) cooling and isolation of the API, polymorph A.

Priority Applications (4)

Applications Claiming Priority (3)

Related Child Applications (2)

Publications (2)

Family

ID=21892899

Family Applications (3)

Family Applications Before (1)

Family Applications After (1)

Country Status (13)

Families Citing this family (27)

Family Cites Families (8)

• 2001
  • 2001-11-09 US US10/037,183 patent/US6472563B1/en not_active Expired - Lifetime
• 2002
  • 2002-09-10 US US10/238,204 patent/US6720453B2/en not_active Expired - Lifetime
  • 2002-10-23 EP EP10178918.8A patent/EP2305635B1/fr not_active Expired - Lifetime
  • 2002-10-23 DK DK02786502T patent/DK1446380T3/da active
  • 2002-10-23 AU AU2002349914A patent/AU2002349914B2/en not_active Expired
  • 2002-10-23 PT PT02786502T patent/PT1446380E/pt unknown
  • 2002-10-23 EP EP02786502A patent/EP1446380B1/fr not_active Expired - Lifetime
  • 2002-10-23 DE DE60234629T patent/DE60234629D1/de not_active Expired - Lifetime
  • 2002-10-23 ES ES10178918.8T patent/ES2685100T3/es not_active Expired - Lifetime
  • 2002-10-23 SI SI200230882T patent/SI1446380T1/sl unknown
  • 2002-10-23 CA CA2477642A patent/CA2477642C/fr not_active Expired - Lifetime
  • 2002-10-23 AT AT02786502T patent/ATE450497T1/de active
  • 2002-10-23 EP EP09172739A patent/EP2165999A1/fr not_active Ceased
  • 2002-10-23 WO PCT/US2002/034118 patent/WO2003042165A1/fr active Application Filing
  • 2002-10-23 JP JP2003544002A patent/JP4271574B2/ja not_active Expired - Lifetime
  • 2002-10-23 ES ES02786502T patent/ES2336436T3/es not_active Expired - Lifetime
• 2004
  • 2004-03-23 US US10/806,993 patent/US20040176450A1/en not_active Abandoned
• 2005
  • 2005-02-07 US US11/052,268 patent/US7145036B2/en not_active Expired - Lifetime
• 2006
  • 2006-08-04 US US11/462,637 patent/US7342132B2/en not_active Expired - Lifetime
• 2008
  • 2008-01-14 US US12/013,848 patent/US7479572B2/en not_active Expired - Lifetime
  • 2008-12-04 AU AU2008253696A patent/AU2008253696B2/en not_active Expired
  • 2008-12-05 US US12/329,196 patent/US7732641B2/en not_active Expired - Lifetime
• 2010
  • 2010-01-22 CY CY20101100073T patent/CY1109832T1/el unknown
  • 2010-04-26 US US12/767,043 patent/US8110706B2/en not_active Expired - Fee Related
  • 2010-06-07 US US12/794,991 patent/US7964753B2/en not_active Expired - Fee Related
• 2012
  • 2012-01-04 US US13/343,118 patent/US20120108670A1/en not_active Abandoned

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events